Good Vibrations: The Physics of Music

8. Why a Piano Is Not a Harpsichord

8 Why a Piano Is Not a Harpsichord Rubinstein lowers his hands as he finishes a Beethoven sonata. The audience breaks out in applause. As he rises from his bench and bows, the applause increases, then several people begin to cheer. He bows again and begins to leave the stage. The applause and cheering swell as he disappears behind the curtain. It continues for several seconds, then suddenly he reappears and walks quickly to the piano. As he sits down the hall goes quiet; then he plays the first few bars of a Chopin polonaise, and a roar of delight resounds throughout the crowd. I’ve had the pleasure of hearing Rubinstein and other classical pianists such as Van Cliburn and José Iturbi, as well as many popular pianists such as Peter Nero, Liberace, and Roger Williams. Roger Williams, in fact, got a degree from the university I taught at for many years. Everyone who knows anything about Williams knows that he studied at Juilliard, but few know that he also got a degree from Idaho State University. Interestingly, he also majored in music at Drake University but was expelled for playing “Smoke Gets in Your Eyes” in the practice room. The piano is truly a magnificent instrument: ask any pianist. I have to admit that I played it for many years before I really knew how it worked. It was easy to see the hammers striking the strings, but the sound that came from them seemed amazingly loud, and I wasn’t sure why. I eventually found out that most of the sound wasn’t coming from the strings; it was coming from a large soundboard. To hear a musical sound you have to get a large amount of air vibrating, and a steel string can’t do that. If the string is attached to a soundboard, however, the string transfers the sound to the soundboard, which amplifies it. In short, the soundboard sets a large amount of air vibrating , and it is this vibrating air that impinges on your eardrums. One of the main reasons the piano is so popular is that it is one of the few instruments on which you can play both the melody and the harmony. In this respect it is like an orchestra. The Beginnings If you look inside a piano, you see that it is a relatively complex instrument . It has thousands of moving parts, along with hundreds of strings. The first pianos didn’t have all these parts, and indeed, the piano has evolved over many years. Its origins go back hundreds of years to much simpler stringed instruments. Two of the earliest of these instruments were the psaltery and the dulcimer. The psaltery is so old, in fact, that it was mentioned in the Bible. It consisted of several strings stretched across a frame or hollowed-out gourd, and it was played by plucking the strings, as can be seen in figure 66. The dulcimer, which originated in the twelfth century, was similar to the psaltery, but the strings were struck with small wooden hammers. Aside from the strings there is, of course, little resemblance between the psaltery or dulcimer and the modern piano. The addition of keys was the first significant step in the evolution from a simple stringed instrument to the complex instrument we know today. Keys were actually used first on early organs; they were added to stringed instruments in the fifteenth century. One of the first to use keys was the clavichord. It grew out of Pythagoras’s monochord, which was used to study the relationship between vibrations on a string. 132 Musical Instruments Fig. 66. Girl playing a psaltery. The clavichord had about twenty strings which were caused to vibrate by pushing a bridge, or “tangent,” against them (fig. 67). A given string could be struck at several points, so several different vibrational modes could be initiated in a single string. A damper was used on the shorter section of the string so that it would not vibrate. In at least two respects the clavichord was like the piano: its strings were metal and it had a soundboard (which was not attached to the frame). The clavichord was a favorite family instrument for many years, being frequently found in the homes of the time, but the instrument had a serious problem. You could vary the loudness slightly, depending on how...